Redox Control of Radical‐Based Dynamic Covalent Chemistry: Macrocycle Formation and Electrochemical Deoligomerization of Bis(Dicyanomethyl Radical)‐Substituted Ferrocene

Abstract Dicyanomethyl radicals conjugated with electron donors have attracted renewed interest as building blocks in radical‐based dynamic covalent chemistry (DCC). In this study, we prepared a novel diradical exhibiting DCC properties, composed of two dicyanomethyl radicals as reaction sites and a ferrocene core as a molecular rotor, which can act as a flexible DCC diradical. The diradical spontaneously oligomerized by reversible C─C bond formation between dicyanomethyl radicals to form macrocyclic oligomers with diverse sizes. Mass spectra indicated the existence of macrocycles up to 13‐mer. Variable‐temperature 1 H NMR, ESR, and UV–Vis–NIR absorption measurements confirmed that the intermonomer C─C bonds in the macrocyclic oligomers were much robust to the dissociation by thermal stimuli than those in the dimer of the mono(dicyanomethyl radical)‐substituted ferrocene. Interestingly, the macrocyclic oligomers could be deoligomerized to the dianion of the monomer diradical by electrochemical reduction using the dynamic equilibrium between the macrocycles and linear diradical species formed by the C─C bond dissociation of the macrocyclic species. The macrocyclic oligomers could be regenerated by re‐oxidation of the dianion, and this study demonstrated unique redox control of DCC.